1. Field of the Invention
The present invention relates to a cuff-block for measurement of the finger arterial blood pressure using a non-invasive finger arterial blood pressure monitor.
More particularly, this invention relates to a cuff-block for measurement of the finger arterial blood pressure using a cuff for local pressurization and a cuff-fixing member for firmly attaching the cuff to the finger with some locally supports placed on the portion of the finger joints, so that a blood flow impediment and the hindrance to the finger motion due to the non-invasively measurement of finger arterial blood pressure can be relieved.
2. Description of the Prior Art
Heretofore, as a non-invasive finger arterial blood pressure monitor, there have been available three kind of measurement techniques of the cuff-oscillometric method, the volume-oscillometric method and the volume-compensation method.
The cuff-oscillometric method is the technique using a cuff pressure oscillation made by a vascular pulsation under the cuff and the blood pressure is indirectly estimated from the change of this pressure oscillation pattern.
The volume-oscillometric method is the technique for estimating a blood pressure using a photo-plethysmograph which detects a pulsatile component of vascular volume under the cuff.
Further, the volume-compensation method is the technique in which a vascular volume servo-control system instantaneously controls the cuff pressure so as to make the vascular volume to a reference volume which corresponds to an unloaded vascular volume detected by the volume-oscillometric method.
Therefore, the cuff pressure tracks the intra-arterial blood pressure, and the blood pressure can be monitored indirectly by measuring the cuff pressure.
According to the volume-compensation method, there are advantages of beat-by-beat measurement of systolic, mean and diastolic blood pressure as well as of obtaining a blood pressure wave.
A belt-like cuff with an appropriate width, pressure of which is transmitted to the arteries under the cuff via the subcutaneous tissue, has conventionally been applied for the indirect measurement of the finger arterial blood pressure based on any one of these methods mentioned above.
The cuff pressure is continuously set above intra-venous blood pressure which is much below intra-arterial blood pressure, due to the fact that the cuff pressure is controlled within a range from diastolic to systolic blood pressure in order to measure the finger arterial blood pressure using the above mentioned methods.
By the way, concerning the finger vascular system, two arteries run parallel with the phalanges and veins run beneath the dermal tissue with complicated crossings.
Therefore, it causes blood flow impediment and venous congestion under the cuff and its distal portion that a circumferential pressurization by the belt-like cuff occludes the veins under the cuff in order to measure the finger arterial blood pressure.
Moreover, it causes hindrance to the finger motion at the blood pressure measuring site that the pressurization by the belt-like cuff constricts various muscles and tendons concerned the finger motion and obstructs the subcutaneous tissue volume increasing due to the crooking the finger.